1. Field of the Invention
The present invention relates to a method for the production of a fibrous web, especially a paper and/or cardboard web, as well as to a computer supported quality control system that is suitable for the implementation of the method.
2. Description of the Related Art
There are a multitude of MD quality controls, i.e longitudinal profile adjustments for certain quality parameters of the material web (MD=machine direction). To be considered among these are the retention control/and the control of ash content. The retention control is currently only implemented as a stand-alone solution. Interaction between the retention control and other adjustments are, therefore, not a consideration. However, it has been demonstrated that, in the case of the ash control this can result in an interactive build up of the controls.
In an article “Wet End Controller™ ensures stability prior to the head box” by Dr. M. Schwarz which, among other issues, addresses the reciprocal effects between retention and ash content, a combination of ash control, retention control and on-line balances are recommended.
What is needed in the art is a method for the production of a fibrous web, as well as the computer assisted quality control system, which provides for interaction between the retention controls and ash controls.